tilghman



UNITED STnTns FATENT @rricn,

' l-llflNJAMlN C. 'lllitlllftlAN AND RICHARD A. TILGHMAN, OFPHILADELPHIA, PENNSYLVANIA.

METHOD on reassess-mains eart -season: GLQBULES.

SPEGIFICATION forming part of Letters Patent No. 4.4.6387, datedFebruary 24, 189i. Application tiled March 17, 1390 Serial No. 844,233.(No specimens.)

To ail whom it may concern.-

Be it known that we, BENJAMIN O. TiLeu- MAN and RICHARD A. TILenMAN,bothof the .city and. county of Philadelphia, State of 'Pennsylvania, haveinvented a certain new and useful Improved Method of lvlanufacturingChilled-Iron Globules, of which the following is a'true andexactdescription, reference being had to the accompanying drawings,which form a part of this specification. Our invention relates to themanufacture of chilled-iron globules such as are used in the abradingprocess described in the patent to Benjamin C. Tilghman, Reissue No.7,499, dated February-6, 1877, also to some extent in the sand-blastprocess. These globules are manufactured in the following way: A streamof melted iron is exposed to the action of ahigh-pressure jet of steamor gas with the- 7 2,0 result of atomizing it, and the spray of ironparticles is thrown into the air, Where the particles assume a sphericalform and become chilled on the surface, so as to take a permanent set orform. Then they fall into a tank of water while still intensely hot, andbeing small they are rapidly and thoroughly chilled, becoming intenselyhard. then removed from the water and dried preparatory to being packedfor shipment. At

0 two stages of the above treatment the globules are exposed to theoxidizing influence of the a'irn amely, when the melted metal is sprayedinto the air, when, owing to its great heat, the'iron combines directlywith oxygen,

an actual burning taking place, with the formation of a crust or scalesof dark oxide, and

during the, process of drying, after removal from the chilling-tank,when the wet globules are acted on by the oxygen of the air, 0 forming afriable coat of reddish oxide or rust. This rust is objectionable formany reasons. Nith certain delicate stones it is liable, unless greatcare is used, to stain the surface of the stone, and when used forgiving a frosted surface to metals by means of the sand-blast the rustis hammered into the metal under treatment, injuring its color andappearance. The rusted globules are also unsightly, and the fr ablereddish rust'formed 59 in drying soils whatever it comes in contact witThe globules are The object of our inventionis to manufacture globulesof chilled iron. having casehardened unpolished but bright cleanmetallic surfaces and which will be free from the above-notedobjections. Such globules are in themselves a new article ofmanufacture, having pronounced advantages over the globules, heretoforemade, and as such the subject-matter' of another application for Letters6 Patent filed March 17, 1890, Serial No. 344,234.

Our. present invention consists of the hereinafterdescribed method ofmaking such globules.

- WV-e atomize the melted iron or steel by .means of a high-pressure jetof steam or gas,

as before,but surround the spray of metal by anon-oxidizing atmospheres'uch, for instance, as the gases produced by passing air througha deepbed of ignited fuel. This is 76 most economically and conveniently doneby introducing the non-oxidizing gas around the atomizing-jet in such amanner as to. supply the suck caused by the same completely. Thenon-oxidizing gas is then forced by the atomizing-jet to accompany andenvelop the atomized material until it is received in the Water of thechilling-tank. This treatment efiectually prevents the burning of thesurface of the hotglobules, which are received in the chill- 8o ing-tankfree from the crust or scale formed- When the atomized material isthrown into an atmosphere containing oxygen. In order to-insure theproduction of globules having clean and bright metallic surfaces, it isnowonly necessary to prevent the formation of the friable red oxide inthe process of drying, and this we accomplish by drying the glob ules ina non-oxidizing atmospheree that is, by surrounding them while drying'by an at 0 mosphere deprived of oxygemsuch as is produced by passingair through a deep bed of ignited fuel or by-a gas or vapor produced inany way and which contains no free oxygen, and will while presentexcludeihe air-such, 9 5 for instance, as steam.

Among other experiments we have ascertained that by subjecting the wetglobules to a high heat in drying them we not only dry them more quicklybut also obtain them free from the red rust owing to the rapidvaporization of the water upon their surfaces, the

vapor or steam being driven off at once from the granules directlyexposed to the heatingsurface and forming a protecting atmosphere aroundthem, and also rising through the granules above, driving off the airand effectually excluding oxygen and preventing its injurious action.The same effect of course is produced by passing steam from a boilerinto the chamber containing the granules or by similarly introducing anyno n-oxidizing gases.

In another application which we are about to file wehave claimed,broadly, the method of manufacturing globules by atomizimg them in anon-oxidizing atmosphere and drying them under conditions which precludethe formation of rust, and also specifically a treatment for preventingoxidization in drying, and our present invention is limited to atreatment in which the drying is accomplished in a non-oxidizingatmosphere.

Having now described our invention, what We claim as ne\v,and desire tosecure by Letters Patent, is-

1. The described method of manufacturing chilled-iron globules, whichconsists in atomizing melted metal, chilling the globules in water, andthen drying them in a non-oxidizing atmosphere. i

2. The described method of manufacturing chilled-iron globules, whichconsists in atomizing melted metal in a non-oxidizing atmosphere,chilling the globules in water, and then drying them in anon-oxidizirgatmosphere.

B. C. TILGIIMAN. R. A. TILGHMAN. Witnesses as to B. C. Tilghman:

ARTHUR C. HALL, r HENRY-BLAIR,

'9 Mount SL, Zll'anchester. Witnesses as to R. A. 'lilghman:

' LEWIS R. DICK,

JOSHUA MATLACK, Jr.

